package org.smart4j.framework;

import org.apache.commons.lang3.ArrayUtils;
import org.smart4j.framework.bean.Data;
import org.smart4j.framework.bean.Handler;
import org.smart4j.framework.bean.Param;
import org.smart4j.framework.bean.View;
import org.smart4j.framework.helper.BeanHelper;
import org.smart4j.framework.helper.ConfigHelper;
import org.smart4j.framework.helper.ControllerHelper;
import org.smart4j.framework.util.*;

import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

/*
* 请求转发类
* */
public class DispatcherServlet extends HttpServlet {
    @Override
    public void init(ServletConfig config) throws ServletException {
        //初始化Helper类
        HelperLoader.init();
        //获取ServletContext对象
        ServletContext servletContext = config.getServletContext();
        //注册处理jsp的Servlet
        ServletRegistration jspServlet = servletContext.getServletRegistration("jsp");
        jspServlet.addMapping(ConfigHelper.getAppJspPath() + "*");
        //注册处理静态资源的默认Servlert
        ServletRegistration defaultServlet = servletContext.getServletRegistration("default");
        defaultServlet.addMapping(ConfigHelper.getAppAssetPath() + "*");
    }

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取请求方法与路径
        String requestMethod = req.getMethod().toLowerCase();
        String requestPath = req.getPathInfo();
        //获取Action处理器
        Handler handler = ControllerHelper.getHandler(requestMethod, requestPath);
        if (handler == null) return;
        //获取Controller类及其Bean实例
        Class<?> controllerClass = handler.getControllerClass();
        Object controllerBean = BeanHelper.getBean(controllerClass);
        //创建请求参数对象
        Map<String, Object> paramMap = new HashMap<String, Object>();
        Enumeration<String> paramNames = req.getParameterNames();
        while (paramNames.hasMoreElements()) {
            String paramName = paramNames.nextElement();
            String paramValue = req.getParameter(paramName);
            paramMap.put(paramName, paramValue);
        }

        String body = CodecUtil.decodeURL(StreamUtil.getString(req.getInputStream()));
        if (StringUtil.isNotEmpty(body)) {
            String[] params = StringUtil.splitString(body, "&");
            if (ArrayUtils.isNotEmpty(params)) {
                for (String param : params) {
                    String[] array = StringUtil.splitString(param, "=");
                    if (ArrayUtils.isNotEmpty(array) && array.length == 2) {
                        String paramName = array[0];
                        String paramValue = array[1];
                        paramMap.put(paramName, paramValue);
                    }
                }
            }
        }

        Param param = new Param(paramMap);

        //调用Action方法
        Method actionMethod = handler.getActionMethod();
        Object result = ReflectionUtil.invokeMethod(controllerBean, actionMethod, param);

        //处理Action方法返回值
        if (result instanceof View) {
            //返回jsp界面
            View view = (View) result;
            String path = view.getPath();
            if (StringUtil.isNotEmpty(path)){
                if (path.startsWith("/")){
                    resp.sendRedirect(req.getContextPath() + path);
                } else {
                    Map<String, Object> model = view.getModel();
                    for (Map.Entry<String, Object> entry : model.entrySet()){
                        req.setAttribute(entry.getKey(), entry.getValue());
                    }
                    req.getRequestDispatcher(ConfigHelper.getAppJspPath() + path).forward(req,resp);
                }
            }

        } else if (result instanceof Data){
            //返回JSON数据
            Data data = (Data) result;
            Object model = data.getModel();
            if (model != null){
                resp.setContentType("application/json");
                resp.setCharacterEncoding("UTF-8");
                PrintWriter writer = resp.getWriter();
                String json = JsonUtil.toJson(model);
                writer.write(json);
                writer.flush();
                writer.close();
            }
        }

    }
}